The present invention generally relates to magnetic recording apparatuses for carrying out a recording by selectively using one of two kinds of recording systems, and more particularly to a magnetic recording apparatus for carrying out a recording by arbitrarily selecting and using one of a luminance/color separation recording system and a low band conversion color recording system which is the system employed in an existing magnetic recording and/or reproducing apparatus, where the luminance/color separation recording system independently but simultaneously records a luminance signal and a color signal on two tracks of a magnetic tape by use of rotary magnetic heads and the low band conversion color recording system records on a magnetic tape by use of rotary magnetic heads a frequency division multiplexed signal comprising a frequency modulated luminance signal and a frequency converted carrier chrominance signal which has been frequency-converted into a frequency band lower than a frequency band of the frequency modulated luminance signal.
Presently, a helical scan type magnetic recording and/or reproducing apparatus (hereinafter simply referred to as a video tape recorder or VTR) for home use which plays a magnetic tape having a width of 1/2 inch employs the so-called low band conversion color recording and reproducing system because the recording and reproducing frequency band of the VTR for home use is relatively narrow. According to the low band conversion color recording and reproducing system, a luminance signal separated from a color video signal is frequency-modulated, and carrier chrominance signal separated from the color video signal is frequency-converted into a frequency band lower than a frequency band of the frequency modulated (FM) luminance signal. The FM luminance signal and the frequency converted carrier chrominance signal are frequency-division-multiplexed into a frequency division multiplexed signal, and this frequency division multiplexed signal is recorded on and reproduced from the magnetic tape. Furthermore, in order to improve the tape utilization efficiency, no guard band is formed between two mutually adjacent tracks on the magnetic tape by setting rotary magnetic heads which record the two mutually adjacent tracks to have gaps with different azimuth angles.
However, according to the low band conversion color recording and reproducing system, there are the following problems. Firstly, the recording and reproducing frequency band of the luminance signal and the carrier chrominance signal is limited, and the recording and reproducing frequency band is not quite sufficient for obtaining a high picture quality. Secondly, the frequency converted carrier chrominance signal is a balanced modulated wave when recording an NTSC system or PAL system color video signal, and the signal-to-noise (S/N) ratio becomes poor due to AM noise of the reproduced frequency converted carrier chrominance signal caused by inconsistent contact between the magnetic tape and the rotary magnetic heads. Thirdly, noise is generated in the horizontal direction of the picture due to residual time base fluctuation component (jitter) included in the reproduced carrier chrominance signal. Fourthly, since the azimuth loss effect is insufficient in the low frequencies when the recording is carried out without forming a guard band between the two mutually adjacent tracks, the frequency converted carrier chrominance signal recorded on the adjacent track mixes into the reproduced signal as crosstalk. Hence, measures must be taken to eliminate such crosstalk. As examples of such measures against crosstalk, the phase of the chrominance subcarrier of the frequency converted carrier chrominance signal of the NTSC system or PAL system is shifted by approximately 90.degree. for every one horizontal scanning period at the time of the recording and at the time of the reproduction (for example, as disclosed in a U.S. Pat. No. 4,178,606 in which the assignee is the same as the assignee of the present application), or the phase of only the frequency converted carrier chrominance signal which is recorded on one of the two mutually adjacent tracks is inverted for every one horizontal scanning period.
In order to obtain a reproduced color video signal having a high picture quality compared to that of the VTR employing the low band conversion color recording and reproducing system, it is possible to employ the so-called luminance/color (Y/C) separation recording and reproducing system. For example, a one-body type VTR for broadcasting use having a built-in camera employs the Y/C separation recording and reproducing system. According to the Y/C separation recording and reproducing system, the luminance signal and the color signal are independently but simultaneously recorded on and reproduced from two tracks of the magnetic tape, and a guard band is formed between the two mutually adjacent tracks. However, the Y/C separation recording and reproducing system is not compatible with the low band conversion color recording and reproducing system, and for this reason, it is impossible to carry out the recording and/or reproduction on one existing VTR by arbitrarily selecting the recording and reproducing system from the two systems.
On the other hand, according to the Y/C separation recording and reproducing system, an audio signal is recorded together with a bias signal by a stationary magnetic head, that is, the audio signal is recorded according to the so-called linear recording system. As a result, there is a problem in that the quality of the reproduced audio signal is not high. Furthermore, when designing a VTR so as to carry out the recording by arbitrarily selecting the system from the two systems, it is desirable from the point of view of obtaining a reproduced audio signal of a high quality that the audio signal is recordable by use of the rotary magnetic heads.